Synthesis of highly monodispersed teardrop-shaped core-shell SiO2/TiO2 nanoparticles and their photocatalytic activities

In this study, teardrop-shaped SiO2/TiO2 nanoparticles (TST-NPs) with core-shell structure were fabricated from tetraethoxysilane (TEOS) and tetrabutyl titanate (TBT) by sol-gel method. And these nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy. Photocatalytic activity of teardrop-shaped SiO2/TiO2 nanoparticles after calcination (CST-NPs) was studied towards degradation of methylene blue under sunlight irradiation. The result showed that CST-NPs possessed good photocatalytic activity. The photocatalytic mechanism was also studied by adding different capture agent. Results showed that addition of 0.003 M of I- decreased the degradation of MB more than same amount of Ag+, indicating that the photogenerated holes may play a more essential role than photoinjected electrons in the oxidation of MB. (C) 2015 Elsevier B.V. All rights reserved.